Dental chair.



H. E. WEBER.

DENTALCHAIR.

APPLICATION FILED OCT. 30; 1914.

Patented Aug. 28, 1917.

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Patented Aug. 28, 1917.

3 SHEETSSHEET 2.

IBIS- 5 am lmg E5 A w kill. mm n I F H. E. WEBER. YDENT AL cum.- APPLICATION FILED OCT- 30.19M-

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H. E. WEBER.

DENTAL CHAIR.

APPLICATION men OCT. 30. 1914.

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Patented Aug. 28, 1917.

3 SHE ETSSHEET 3.

HENRY E. WEBER, 0J5 CANTON, OHIO, ASSIGNOR TO THE WEBER DENTAL MANUFAC- TUBING COMPANY, OF CANTON, OHIO, A. CORPORATION OF OHM).

DENTAL CHAIR.

To all. whom it may concern:

Be it known that T, HENRY E. WEBER, a citizen of the United States, residing at Canton, in the county of Stark and State of Ohio, have invented certain .new and useful Improvements in Dental Chairs, of which the following is a specification.

The invention relates to adjustable chairs which are adapted to be vertically raised and lowered on the base, the raising and lowering being accomplished by a hydraulic jack. In chairs of this type it is diflicult to sustain the chair in a given position of elevation, for the reason that the slightest leakage of the oil or other liquid employed in the lifting jack permits the seat of the chair to subside or drop downward a corresponding distance, and it is practically impossible to make and maintain the valves and pistons of the ack with such closely fitting parts as to prevent a recurrence and continuance of a leakage of the liquid and a corresponding settlement of the chair seat.

The principal objects of the present invention are to provide a quick acting release valve for the liquid in the cylinder of the jack, that will reduce the leakage to a minimum; to provide automatic means for l0cking and positively sustaining the chair standards when raised to a given position; to provide means for disengaging said looking means immediately in advance of opening the release valve for lowering the chair; and to provide automatic means for gradually closing the release valve to cushion the seating of the sliding standards upon the base and avoiding a shock to the chair seat and its occupant.

These objects of the invention, and ancillary advantages, are attained by the construction, mechanism and arrangement illustrated in the accompanying drawings, forming part hereof, in which- Figure 1 is a plan view of the extensible standards and base for a dental chair;

Fig. 2, anupright section, generally on line 22, Fig. 1, showing the standards partially raised or extended;

Fig. 3, a detached elevation, partly in section, of the releasing and locking devices, as when the standards are raised and locked;

Speciitcation of Letters Patent. Patenfiygdl Aug, 23 1191'? Application filed October 30, 1914. Serial No. 869,412.

Fig. 4, a similar view, as when the lock is dlsengaged for opening the release valve;

Fig. 5, a similar view, as when the release valve has been opened; a

F g. 6, a fragmentary section of the release valve;

- Fig. 7, a detached plan view of the lock-' ing dog; and

8, a section of same on line 8-8, Fig.

Similar numerals refer to similar parts throughout the drawings.

The chair base 1, the base standard 2, the

locking standard 3, the intermediate standard 4, and the seat standard 5, may he of the general construction and arrangement shown in my Patent'No. 958,048, dated May 17, 1910; and the pump 6 with the plunger 7 therein, the cylinder 8 with the piston 9 therein, and the intervening check valve 10, for elevating the extensible standards by means of a liquid contained in the base standard, may be of any suitable type or form of such parts employed in a lifting jack of this character, and the details of construction thereof are not necessary parts of the present invention.

The case 11 of the release valve 12 is formed or secured on one side of the base or bottom 13 of the cylinder of the jack and extends radially therefrom to the wall of the base standard, with which, however, it is not connected. The valve 12 is shaped with the conical end 14 adapted to seat in the outer end of the release port 15 c0mmunicat ing with the lower end of the cylinder; and the valve is preferably swiveled in the end of the screw stem 16, as by means of the cylindric head 17 located in the cylindric recess 18 in the forward end of the stem, between which head and the internal rim flange 19 in the end of the stem may be provided the compression spring 20 for normally holding the head of the valve against the stop 21 formed by the inner endof the recess.

The valve and its head are loosely fitted in the surrounding parts of the screw stem, so that the conical end of the valve may have a certain amount of lateral play, thereby enabling it to truly find its seat when it is closed by being moved toward and into the outer end of the release port. By thus loosely swiveling the conical valve in the end i its seat to open the port when the stem is I screwed outward therefrom.

The stem 16 is provided with the steep thread 22 operating in the corresponding groove 23 provided in the case, for moving the valve to and from the release portb a rotation of the stem; and on the outer en of the stem is secured the pinion 24 meshin with the rack 25 secured on the lower end 0 the upright actuating rod 26, by the vertical movements of which the valve is opened and closed. The valve case is preferabl made with the guide 27 for the rack, the earin 28 for the outer end of the valve stem, an the recess 29 for receiving thepinion and permitting a lateral movement thereof with the endwise movement of the stem, during which movement the teeth of the pinion slide laterally upon the teeth of the rack.

The rack 25 is provided with the tubular stem 25' having the lower cylindric socket 30 therein for the compression spring 31, and the larger upper cylindric socket 32 therein for the head 33 on the sliding shank 34 on the lower end of the actuating rod 26, below which head the centering pin 35* may extend downward into the compression spring.

By a compression of the spring 31, the head 33 on the sliding shank may rest on the stop 36 formed at 'thelower end of the upper cylindric socket, and the bushing 37. is adjustably secured, as by screwing, therein; the lower end of which bushing forms the stop 38 for the head to limit the upward sliding movement of the same; which bushing may .be fixed in an desired position of adjustment by the loc nut 39. By this construction and arrangement, the actuating rod and the rack on its lower end, may be slightly extended with reference to each other, within the, extent of positive stops in each direction, and the compresslon spring serves to hold the same in extended relation to the extent of the strength of the p The actuating rod 26 for the release valve is slidably mounted in upright position in.- the guide bearings 40 and 40' formed .or provided in the lugs 41 and 41' formed or secured on the inner side of the wall of the base standard; and the upper bearing 40' may be in the form of an adjustable bushing, as shown; 'between which bushing and the shoulder 42, formed on the rod above the lower bearing 40, is provided the controlling compression spring 43 located around the reduced upper end portion 26' of the rod, which spring serves to normally hold the actuating rod downward to rotate and hold the release valve in closed position, with the expansion sprin 30 compressed, and thehead of the sliding stem, stopped on the shoulder 36 in thetubular stem of the rack, as shown in Fig. 3, which is the normal position of the parts when the release valve is closed.

The locking dog 44 is mounted by the pivot 45, adjacent to the upper end of the actuating rod 26, in the bracket 46 formed or secured on the upper end of the base standard 2; which dog is provided with a plurality of cam teeth 47, 47 and 47" on its free end adapted to engage and bite into the adjacent face 48 of the intermediate standard 4 for clamping and locking the same by a wedging cam action to prevent the said standard from dropping or moving downward with respect to the base standard when elevated therein and engaged by the cam teeth of the dog.

The second or intermedlate tooth 47' is located farther than the first or lower tooth 47- from the axis of the pivotal bearing of the dog, and likewise the third or upper tooth 47 is located a little farther than the intermediate tooth from the axis of the pivotal tooth, and the intermediate tooth protrudes slightly beyond the plane of the first and third teeth; so that the gripping effect of each one of the second and third teeth is greater than the previous one brought into play. To designate the difference in the distance of the several teeth from the plvotal axis of the cam dog, they are referred to herein as differential teeth.

The parts are so constructed 'and arrangedthat the first or lower cam tooth 47 on the end of the dog normally rests in wedging engagement with the face 48 of the intermediate standard by the weight of the dog, which may be supplemented by the action of one or more springs 49 located in the sockets 50, and abutment pins 51 having their inner ends sliding endwise in the sockets and their outer ends in sliding contact with the stop face 52 provided in the supporting bracket of the dog; and the pendent foot 53 is provided on the dogin the path of the head 54 secured on the upper end of the actuating rod 26, by the upward movement of which head the dog is adapted to be lifted and rotated upon its pivot to move the cam teeth free from the adjacent face of the intermediate standard, as shown in Figs. 4 and 5. When, however, the actuating rod is held downward by its controlling spring 43 in its position for closing the release valve, the head 54 on its upper end is 1,2ee,eoe

located at a slight interval below the foot 53 of the locking dog, so that the cam teeth thereof may drop and rotate downward into wedging engagement With the adjacent face of the intermediate standard.

The usual release lever 55 is fulcrumed on the pivot 56 mounted in the Wall of the base standard, which lever is provided with the pedal 57 on its outer end, and the arm 58 on its inner end engaging under the cross pin 59 on the actuating rod, by means of which this rod may be operated upward against the action of the controlling spring 43, by the operators foot upon the pedal; and the usual pump lever 60 is fulcrumed on the pivot 61 also mounted in the wall of the base standard, which lever is provided with a suitable pedal 62 on its outer end and the arms 63 on its inner end engaging over the oscillating fingers 64 pivoted to the stem 65 of the pump plunger 7, by means of which the plunger is operated downward against the action of the controlling spring 66, for raising or elevating the chair standards by pumping the liquid into the cylinder of the lifting jack, all in a manner well known in the art.

The step 67 is formed or secured on the stem 25 of the rack, as by means of the collar 68 secured between the bushings 69 and 69' screwed on the stem; which step is positioned in the path of the abutment pin 0 slidingly mounted in the bore 71 in the lower end of the intermediate standard, wherein it is held upward by the stop screw 72, and is cushioned against upward movement by the compression spring 73 in the bore; and these parts are so arranged that the release valve will be automatically closed by the spring cushioned contact of the pin against the step as the intermediate standard approaches its seat upon the base standard when dropped or moved downward therein, thereby preventing a shock or jar when the several standards are finally stopped at the end of the downward movement.

The lug 74 is provided on the lower end of the intermediate standard in the path of the head 54 on the actuating rod 26, by means of which the release valve is gradually opened as the intermediatestandard approaches the end of its proper upward movement, thereby preventing an elevation of the standards beyond the extent of their respective guides.

In the operation of the'chair it is evident that the controlling spring 43 will normally hold the release valve actuatingrod downward for holding the valve closed, as shown in Figs. 2 and 3; in which relation of the parts the foot 53 of the locking dog is not supported by the head on the actuating rod, and the first cam tooth of the dog rests in wedging engagement against the face 48 of tooth 47 will bite the intermediate standard. Whenever the standards are extended upward by an operation of the ward along the tooth of the locking dog, which rests against it, and the relation of these parts remain in the position shown in Figs. 2 and 3 as long as there is no leakage from the cylinder through the release valve, or otherwise, to permit a downward movement or dropping of the standards.

It is evident, however, that should there be such a leakage, the cam action of the first into the adjacent face of the intermediate standard, and if the downward movement continues far enough, the second tooth 47 of the dog will impinge said face, by a wedging cam action, whereby the intermediate standard is rigidly clamped between the locking dog and the opposing guides of the base standard, so that the intermediate standard will be stopped against any further downward movement and will be held rigidly against any lateral movement with respect to the base standard.

Should there be a considerable looseness between the guides of the standards, the upper or third cam tooth on the locking dog might be brought into play, but it has been found in practice that the clamping range of the second tooth is usually sufiicient to clamp and lock the intermediate standard to the base standard. 7

In event the second or third tooth shall have been brought into play, or the first tooth shall be so engaged by the abutting face of the intermediate standard as to prevent a disengagement of the same by an elevation of the actuating rod of the release valve, it is only necessary to slightly elevate the standards by a single depression of the pump lever, whereupon the locking dog is raised into the position where its lower tooth merely rests against the face of the intermediate standard, as shown in Fig. 3. a

When the parts are in this relation, and it is desired to drop the extended standards downward, the foot of the operator is applied to the pedal of the release lever, and a depression of the same serves to elevate the actuating rod of the release valve. It is evident, however, that the rack 25 on the lower end of the actuating rod will notbe raised by the first portion of this movernent because ofthe extensible connection between the rack and the rod, until the head 7 33 has impinged the lower end of the bushing 38, as shown in Fig. 4; during which initial movement of the actuating rod, the

head 54 thereon impinges the foot of the locking dog and the teeth therefore are swung free of the adjacent locking face 48 of the intermediate standard, as shown in Fig. 4, and during this initial movement of pump, it is evident that the intermediate standard is free to shde upare mits the extended standar the actuating rod, the release valve remains closed.

A further elevation of the actuating rod, however, carries with it the rack on its lower end into the position shown in Fig. 5, thereby rotating the release valve in the direction to withdraw its conical end from its seat in the release port, as shown in Fig. 6, thereby permitting an escape ofthe liquid fromthe cylinder of the 'ack, which pers to drop downward; and it is evident that the same further raising of the actuating rod lifts the locking dog and rotates the cam teeth thereof entirely away from the lockin face of the intermediate standard, as s own in Fig. 5. a

I claim:

1. A chair base including abase standard and one or more extensible standards, a wedging dog having difierential teeth mounted on one standard with one tooth normally resting against another standard for locking the same against downward movement.

2. A chair base including a base standard and one or more extensible standards, and

a cam dog having differential teeth pivoted on one standard with one tooth normally resting against another standard for looking the same against downward movement.

3. A chair base including a base standard and one or more extensive standards,

I for locking movement, and means for movmg the dog a wedging dog having difierential teeth mounted on one standard with one tooth normally resting against another standard the same against downward on the one standard for disengaging it from the other standard.

4. A chair base and one or more extensive standards, a cam dog having difierential teeth pivoted on one standard with one tooth normally resting "a wedging dog having against another standard for locking the same against downward movement, and on the one standard for disengaging it om the other standard.

5.-A chair base including a base standard and one or more extensible standards, differential teeth mounted on one standard with one tooth normally resting against another standard for locking the same against downward movement, a lifting jack in the base standard, and releasing means for the jack acting to disengage the wedging dog before releasing the jack.

6. A chair base including abase standard and one or more extensible standards, a wedging dog mounted on one standard normally resting against another standard for locking the same against downward moveand including a base standard 'screw stem havin ment, a liftin jack in the base standard, and an extensi 1e actuating rod for releasing the 'ack arranged to disengage the wedgmg 0g by its extension and to release the Jack when extended.

7 A chair base including a base standard and one or more extensible standards normally seated in the base, a lifting jack in the base standard, an actuating rod for releasing the jack having a step thereon, and a sprmg-cushioned pin on one of theextensible standards in the path of the step for gradually stopping the jack as said extensible standard approaches its seat in the base.

8. A chair base including a base standard and one or more extensible standards, a hydraulic jack 'for extending the standards, and releasing means for the jack including a screw' stem having a valve swiveled at one end.

9. A chair base including a base standard and one or more extensible standards, a hydraulic jack for extending the standards, and releasing means for the jack including a screw stem having a valve loosely swiveled at one end.

10. A chair base including a base standard and one or more extensible standards, a

hydraulic jack for extending the standards and having a release port, and releasing means for the uni: including a screw stem having a valve swiveled at one end, said 7 valve havlng a conical end adapted to seat hydraulic jack for extending the standards and having a release port, and releasing means for the jack including a screw stem having a valve loosely swiveled in its end, said valve having a conical end adapted to seat in the opening of the port.

12. A chair base including a base standard and one or more extensible standards, a hydraulic jack for extending the standards, releasing means for the jack including a screw stem having a valve swiveled at one end and a pinion on the other end, and an actuating rack engaged with the pmion.

13. A chair base including a base standard and one ormore extensible standards, means for locking the standards together, a hydraulicjack for extending the standards, releasing means for the jack including a a valve on one end and a pinion on the ot or end, and an actuating rod having a rack extensibly connected therewith engaging with the pinion for initially disengaging the lock and subsequently opening the valve.

14 chair base including a base standard and one or more extensive standards, a wedging dog having difierential teeth mounted on one standard with one tooth normally resting against another standard ing a valve loosely swiveled at one end, with for locking the same against downward yielding means for holding the valve in nor- 1o movement, and spring means bearing on one mal position.

standard for pressing the dog against an- 5 other standar I HENRY WEBER 15. A chair base including a base stand- Witnesses: ard and one or more extensive standards, a EARL C. CARLSON,

hydraulic jack including a screw stem hav- LOUIsEM. OORBY. 

